Stripe: change credit card number? - php

Question

I'm using Stripe Payments and would like to give customers the possibility to change their credit card. Referring to https://stripe.com/docs/api#create_subscription -> source, I tried the following PHP-code:
$customer = \Stripe\Customer::retrieve($client_id);
$customer = \Stripe\Customer::create(array(
"source" => $token) //the token contains credit card details
);
This works, but unfortunately it unintentionally also creates a new customer ID:
The original customer ID was cus_6elZAJHMELXkKI and I would like to keep it.
Does anybody know the PHP-code that would update the card without creating a new customer?
Thank you very much in advance!
PS: Just in case you need it – this was the code that originally
created the customer and the subscription:
$customer = \Stripe\Customer::create(array(
"source" => $token,
"description" => "{$fn} {$ln}",
"email" => $e,
"plan" => "basic_plan_id")
);
\Stripe\Charge::create(array(
"amount" => 10000, # amount in cents, again
"currency" => "eur",
"customer" => $customer->id)
);

Answer 1

I've just found the answer, maybe it helps someone of you, too:
You can replace the old card with the new one like so:
$customer = \Stripe\Customer::retrieve($client_id);
$new_card = $customer->sources->create(array("source" => $token));
$customer->default_source = $new_card->id;
$customer->save();

Answer 2

The answer helped a bunch but commenter was correct that old card wasn't deleted.
Assuming you would only ever have one card for a customer you would do this instead:
//get customer
$customer = \Stripe\Customer::retrieve($client_id);
//get the only card's ID
$card_id=$customer->sources->data[0]->id;
//delete the card if it exists
if ($card_id) $customer->sources->retrieve($card_id)->delete();
//add new card
$new_card = $customer->sources->create(array("source" => $token));
$customer->default_source = $new_card->id;
$customer->save();